Apparatus for dressing grinding wheels



1970 J. VAN DEN KIEBOOM 3,490,431

APPARATUS FOR DRESSING GRINDING WHEELS Filed May 5, 1967 3 Sheets-Sheet 1 //l/V'/V7'O/ JOHANNES L. VAN DEN KIEBOOM dfiw WW I W ATTOE/VEYS Jan. 1970 J. VAN DEN KIEBOOM 3,490,431

APPARATUS FOR DRESSING GRINDING WHEELS Filed May 5, 1967 3 Sheets-Sheet 2 v F H" TZH z :5 W296 m2 I 45 T'JG. 2

//V!/EN7'O2 JOHANNES L. VAN DEN KIEBOOM Jan. 1970 J. L. VAN DEN KIEBOOM 3,490,431

APPARATUS FOR DRESSING GRINDING WHEELS Filed May 5, 1967 3 Sheets-Sheet 3 //VVE/V7'OE JOHANNES L. VAN DEN KIEBOOM A TTOENEYS United States Patent 3,490,431 APPARATUS FOR DRESSING GRINDING WHEELS Johannes L. van den Kieboom, St. Clair Shores, M1ch., assignor to La Salle Machine Tool, Inc., Warren, Mich., a corporation of Michigan Filed May 5, 1967, Ser. No. 636,432 Int. Cl. B28d 1/16; B24b 49/00, 51/00 US. Cl. 125-11 1 Claim ABSTRACT OF THE DISCLOSURE CROSS REFERENCE TO RELATED APPLICATION The apparatus of this invention is particularly useful in dressing the work surfaces of the grinding wheels disclosed in applicants copending application Ser. No. 636,- 533, filed May 5, 1967.

Background of the invention This invention relates to automatic apparatus which operates periodically to dress grinding wheels. In some automation apparatus wherein a grinding operation is utilized for finishing a particular surface or surfaces on workpieces that are continuously fed through the grinding apparatus, the grinding wheel work surfaces which must be periodically dressed are difficult to locate precisely at a given time because of small size variations in the workpieces. For example, in the grinding apparatus disclosed in the aforementioned patent application, disk brake assemblies are automatically ground in the apparatus by first locating the grinding wheels against the surfaces to be ground while the grinding wheels are more or less floatingly supported. Following this engagement, the grinding wheels are firmly supported and advanced to remove predetermined amounts of material from the faces to be finished. This arrangement is necessary in order to avoid unnecessary grinding of workpieces that are oversize relative to other workpieces due to tolerance buildups. The apparatus of this invention is capable of periodically dressing the grinding wheels in apparatus of this type by first locating the dressing tool relative to the workpiece to in turn thereby automatically locate the dressing tool relative to the grinding wheel work surface to be dressed. No pertinent prior art dealing with this problem or showing apparatus capable of handling this problem is known.

Summary of the invention The dressing apparatus of this invention is capable of dressing a grinding wheel surface disposed in a predetermined position with respect to a workpiece face. The apparatus includes a frame, a bar member slidably supported dressing tool in a plane parallel to the grinding wheel work surface. As a result, the bar member can first be slidably face. The dressing tool can then be moved through this plane to remove an amount of material from the grinding wheel work surface corresponding to the distance between this surface and the plane in which the dressing tool is moved. Thus, a uniform dressing of the grinding wheel can be periodically accomplished even though the exact location of the grinding wheel work surface, by itself, is unknown in each instance because of size variations in the workpieces and wear of the work surface. The apparatus of this invention thus provides for continual automatic and accurate dressing of a grinding wheel in automated apparatus for grinding parts of non-uniform size.

Description of the drawing FIGURE 1 is a plan view of grinding apparatus in which the grinding wheel dressing apparatus of this invention is utilized;

FIGURE 2 is an elevational view of the grinding wheel dressing apparatus of this invention disposed at one of the stations in the apparatus illustrated in FIG. 1, with some parts broken away and other parts shown in section for the purpose of clarity; and

FIGURE 3 is an end view of the apparatus of this invention looking in the direction of the arrow 3 in FIG. 2, and showing the location of the grinding wheel in section.

Description of the preferred embodiment With reference to the drawing, the dressing apparatus of this invention, indicated generally at 10 is illustrated in FIG. 1 as forming a part of a pair of machine assemblies 12 and 14 employed for coarse and finish grinding, re spectively, of workpieces, indicated at 16, which in this case are disk brake members. Two grinding assemblies 13 are illustrated in FIG. 1 in the machine assemblies 12 and 14 which are described in detail in the aforementioned copending application. Feeding apparatus indicated gen erally at 18, delivers workpieces to a transfer assembly, indicated generally at 20, which moves the workpieces through the six stations, illustrated in FIG. 1, formed by the assemblies 12 and 14. Stations #2 and #5 are grinding stations at which the apparatus 10 of this invention is employed for grinding wheel dressing purposes.

As shown in FIG. 2, the workpiece 16 consists of a disk member 15 having opposite brake faces 17 and 19 and a radially inwardly extending flange 21. A bearing sleeve 23 has a flange 25 secured to the flange 21 and is f rmed at opposite ends with bearing cups 27. At stations #2 and #5, a workpiece 16 delivered by the transfer assembly 20 is in a position in which the bearing cups 27 are centered on a spindle 22 on a driving head 24 and a spindle 28 on the frame for back and forth movement in directions substantially perpendicular to the work surface on the grinding wheel, and a stop on the bar member which is engageable with the workpiece surface that has just been ground on the workpiece. surface that has just been ground on the workpiece. A bracket is fixedly mounted on the slidable bar for movement therewith, and a dressing tool is mounted on the bracket so that it is in a predetermined spaced relation with the stop measured in a direction perpendicular to the grinding wheel work surface.

Also mounted on the bracket is means for moving the.

on a live center unit 30. A motor 26 drives the head 24 so as to rotate the workpiece 16.-Thus at stations #2 and #5, the workpiece 16 is rotated about the axis of the spindle 22. During such rotation, the opposite faces 17 and 19 of the disk member 15 are disposed between a pair of tubular grinding wheels 36 and 38. The grinding wheels 36 and 38 are actuated by substantially identical support and drive assemblies 40 and 42, respectively, shown in FIG. 1, so that the wheels 36 and 38 are continuously rotating about their axes. Each of the grinding wheels 36 and 38 has a working surface 44 and 46, respectively, which engages the disk member faces 17 and 19, respectively, for grinding these faces. Each of these surfaces 44 and 46 must be periodically dressed, and this is the function of the apparatus 10 of this invention.

The apparatus for each of the machine assemblies ,7

12 and 14 is identical, so that only one apparatus 10 is described in detail hereinafter. As shown in FIGS. 1 and 2, the apparatus 10 consists of a stationary frame 50 having a central opening 52 and providing a support for a horizontally shiftable bar member 54. Compression springs 56 and 58 engage opposite ends 60 and 62, respectively, of the bar member 54 so that they urge the bar member 54 in opposite horizontal directions asviewed in FIG. 2. In other words, the spring 56 urges the bar member 54 toward the right in FIG. 3 and the spring 58 urges the bar member 54 to the left, as viewed in FIG. 2.

A pair of fluid actuated cylinder assemblies 64 and 68 are mounted on side extensions 51 of the frame 50. The cylinder assembly 64 has a piston rod 66 which engages the spring 56 so that on extension of the piston rod 66, the spring 56 will be compressed so as to urge the bar member 54 to the right with increased force and on retraction of the piston rod 66 the spring 58 can move the bar member 54 to the left. The cylinder assembly' 68 is provided with a piston rod 70 which engages the end of the spring 58 so that on extension of the piston rod 70 the spring 58 will be compressed so as to urge the bar member 54 to the left as viewed in FIG. 2 with increased force, and on retraction of the piston rod 70 the spring 56 can move the bar member 54 to the right.

A fluid actuated cylinder assembly 72 mounted in an upright position on the frame 50 has a piston rod 74 provided on its terminal end with a clamp plate 76. When the cylinder assembly 72 is actuated to extend the piston rod 74, the clamp plate 76 is engageable with one side of the bar member 54 so as to hold the bar member 54 in a moved position. On actuation of the cylinder assembly 72 to retract the piston rod 74, the clamp plate 76 is moved into a clearance relation with the bar member 54, so that the bar member 54 can again be shifted horizontally.

A bracket 78 (FIGS. 2 and 3) is fixedly secured to the bar member 54 at a position such that the bracket 78 extends into the space 52 in the frame 50. A fork-shape member 80 having horizontally spaced legs 82 and 84 extends downwardly from the bracket 78, as shown in FIG. 2. A stop member 86 is mounted on the leg 82 and a stop member 88 is mounted on the leg 84. The stop members 86 and 88 are substantially identical each having a terminal end 89 and having an axial air passage 90 ex tending therethrough. This passage 90 is connected to a supply of air under pressure for a purpose to appear pnesently.

The bracket 78 (FIG. 3) includes a horizontal leg 92 which carries a horizontally extending pivot 94. An arm 96 is rotatably supported intermediate its ends on the pivot 94 so that the arm 96 can be swung in a substantially vertical plane about the pivot 94. A pair of dressing tools 98 and 100 are mounted on one end of the arm 96 so that they project in opposite substantially horizontal directions, with each of the tools 98 and 100 having a working face 102 in which abrasive elements such as diamonds are mounted. The opposite end of the arm 96 is pivotally connected to the piston rod 104 for a fluid actuated cylinder assembly 106 having a cylinder 108 pivotally supported on a pin 110 carried by the bracket 78. As shown in FIG. 3, when the piston rod 104 is extended, the dressing tools 98 and 100 are in the upper positions illustrated in solid lines, and when the piston rod 104 is retracted, the dressing tools 98 and 100 are swung downwardly in a substantially vertical plane to the lower position shown in broken lines. Thus,.on retraction of the piston rod 104, the dressing tools 98 and 100 are swung through an arc, indicated at 112 in FIG. 3, which is disposed in a substantially vertical plane. An adjustable switch actuating assembly 114 is attached to the piston rod 104 for actuating a pair of limit switches 116 and 118 4 in the upper and lower positions, respectively, of the dressing tools 98 and 100.

It can thus be seen that since the dressing tools 98 and 100 and the stops 86 and 88 are mounted on the bracket 78 which is fixed on the reciprocatable bar member 54, the working faces 102 of the dressing tools 98 and 100 are always in predetermined spaced relation, measured in a horizontal direction, with the stop ends 89. As a result, by locating a stop end 89, the location of the dressing tool work faces 102 is known.

In the operation of the grinding wheel dressing apparatus 10 of this invention, assume that dressing of the work surface 44 on the grinding wheel 36 is desired. The pressure in the cylinder assembly 64. is relieved so that the piston rod 66 can move rearwardly, as shown in FIG. 2. The spring 58 then urges the bar member 54 to the left, as viewed in FIG. 2, until the end 89 of the stop 88 engages the workpiece face 17. The spring 58 is then unable to move the bar member 54 further in this direction, and this condition is sensed by a switch (not shown) which is sensitive to the fact that air can then no longer flow through the passage 90 in the stop member 88, This causes the cylinder assembly 72 to extend the piston rod 74 and move the clamp plate 76 into clamping engagement with the bar member 54 to retain the bar member 54 in its moved position. At this time the piston rod 104 is in its extended position shown in solid linesin FIG. 3. Switch apparatus (not shown) associated with the piston rod 74 is then actuated to cause the cylinder assembly 106 to retract the piston rod 104 to move the dressing tool 100 along the are 112 to dress the wheel surface 44.

The working face 102 of the dressing tool 100 is located a pre-determined distance back from the end 89 of the stop 88. As a result, during movement of the tool 100 along the are 12, the working face 102 thereof operates to dress the working surface 44 of a grinding wheel 36. This dressing can take place either at the time the grinding wheel is engaged with the workpiece face 17 or after the wheel has been moved back from the face 17 a predetermined small distance. The latter is preferred because it involves less movement of material removed from the grinding wheel onto the Work. In such case, the dressing tool face 102 is located further back from stop end 89 by an amount equal to the spacing between tool face 44 and work face 17 than is the case when the dressing is done While these latter faces are engaged. In one embodiment of the invention, the grinding wheel work surface 44 is dressed by removing material to a depth of approximately 0.002".

It can thus be seen that the working face 44 of the grinding wheel 36 is located by first locating the face 17 with the stop member 88. The grinding wheel 36 can then be dressed either while its working face. 44 is in engagement with the face 17 or after it has been backed off from face 17 a known distance, since at such time the surface 44 can be located by locating the face 17. Since the face 17 on a number of workpieces 16 traveling through station #2 will not always be in the same position, this arrangement insures proper dressing of the grinding wheel work surface 44 without unnecessary removal of material from the grinding wheel 36. The grinding wheel 38 (FIG. 1) is similarly dressed utilizing the stop 86 and the dressing tool 98.

Once the dressing tool 100 has been moved to its lower position illustrated in broken lines in FIG. 3, the limit switch 116 is actuated to cause the cylinder assembly 106 to extend the piston rod 104 and return the tool 100 to its upper position shown in solid lines. This condition is sensed by actuation of the switch 118 which in turn causes the cylinder assembly 72 to retract the piston rod 74 and causes the cylinder assembly 64 to return the member 54 to a position in which the work support is located so that the stops 86 and 88 are in a spaced relation with respect to workpieces 16 traveling through station #2. The apparatus is then in position for repeating the above described cycle at intervals of time necessary to keep the grinding wheel work surfaces in the desired condition.

From the above description it is seen that this invention provides apparatus for dressing a pair of grinding wheels 36 and 38 when the positions of the working surfaces 44 and 46 of the grinding wheels are, by themselves, unknown at all times due to the nonuniformity of the workpieces 16 and wear of the wheels 36 and 38. In other words, the working surface 44 of the Wheel 36 is not always in the same position relative to the frame 50 when a workpiece is being ground, because of the nonuniformity of the workpieces, and the work surface 44 is not in the same position when the wheel 36 is retracted relative to workpieces 1-6 because the surface 44 wears during use. The apparatus of this invention provides stops 86 and 88 which are shiftable in directions perpendicular to the grinding wheel surface 44 and are always in predetermined positions relative to dressing tools 98 and 100 measured in the same direction. Thus, the provision for movement of the dressing tools 98 and 100 in planes perpendicular to the direction of movement of the bar member 54 insures the predetermined desired dressing of the grinding wheel work surfaces 44 and 46 in each instance.

It will be understood that the apparatus for dressing grinding wheels which is herein disclosed and described is presented for purposes of explanation and illustration and is not intended to indicate limits of the invention, the scope of which is defined by the following claim.

What is claimed is:

1. Apparatus for dressing a grinding wheel surface disposed in a predetermined position with respect to a workpiece face, said apparatus comprising a frame, a support bar slidably mounted on said frame for back and forth movement in directions substantially perpendicular to said surface, a dressing tool, means mounting said dressing tool on said support bar for movement in a plane substantially parallel to said surface, stop means on said support bar spaced a predetermined distance from said dressing tool measured in a direction perpendicular to said surface so that when said support bar is moved to a position in which said stop means is engaged with said workpiece face said dressing tool is movable in a plane located a predetermined distance from said grinding wheel surface, opposed spring means urging said support bar in opposite directions, fluid actuated cylinder means mounted on said frame and associated with said spring means for enabling said spring means to slide said bar in said directions, and clamp means mounted on said frame and engageable with said bar for clamping said bar in a moved position.

References Cited UNITED STATES PATENTS 2,077,363 4/ 1937 Hulbert 11 2,082,736 6/1937 Indge 12511 2,148,120 2/1939 Hall 12511 3,3 30,074 7/ 1967 Stuckey 51238 HAROLD D. WHITEHEAD, Primary Examiner Us. or. X.R. 51-165 

